Angiomyolipoma volumes and pulmonary-function tests in patients with LAM were assessed during the period of sirolimus treatment, from baseline to 12 months, and during a post-treatment observation period, from 12 to 24 months. At baseline, 18 patients had LAM, but pulmonary data were uninterpretable in 2 patients because of chylothorax or pneumothorax. At the 12-month time point, one patient declined to undergo pulmonary-function tests, and four patients had withdrawn from the study. One patient withdrew during the second year.